How severe is CVE-2019-11705?

CVE-2019-11705 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-11705 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 10% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-11705?

CVE-2019-11705 affects Mozilla Thunderbird. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-11705?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2019-11705 published?

CVE-2019-11705 was published on 2019-07-23 and last updated on 2026-06-17.

CVE-2019-11705

CVE-2019-11705 is a critical-severity vulnerability in Mozilla Thunderbird with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 10% (95th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Mozilla Thunderbird
Published: 2019-07-23
Last modified: 2026-06-17

Description

A flaw in Thunderbird's implementation of iCal causes a stack buffer overflow in icalrecur_add_bydayrules when processing certain email messages, resulting in a potentially exploitable crash. This vulnerability affects Thunderbird < 60.7.1.

Frequently asked questions

What is CVE-2019-11705?: A flaw in Thunderbird's implementation of iCal causes a stack buffer overflow in icalrecur_add_bydayrules when processing certain email messages, resulting in a potentially exploitable crash. This vulnerability affects Thunderbird < 60.7.1.
How severe is CVE-2019-11705?: CVE-2019-11705 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-11705 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 10% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-11705?: CVE-2019-11705 affects Mozilla Thunderbird. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-11705?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2019-11705 published?: CVE-2019-11705 was published on 2019-07-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

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